Luminous gun sight



Patented Dec. 14, 12943 LUMINOUS GUN SIGHT George Howlett Davis,Detroit, Mich.

Application October 1940, Serial No. 359,649

9 Claims.

This invention relates to sighting devices for firearms and inparticular to luminous gun sights for use at night or in dark places, orwhere the light is dim.

One object of this invention is to provide a luminous gun sight forfirearms and having means for optically projecting upon the target aluminous pattern such as cross lines, a circle, or other indicia at thepoint of impact of the bullet at the end of its trajectory.

Another object of the invention is to provide a luminous gun sight asset forth in the preceding object wherein the device is self-containedand compact, and is attachable or detachable at will from the gun.

Another object is to provide a luminous gun sight as set forth in thepreceding object wherein a spot on the target is brilliantly illuminatedby reason of the use of a source of electricity, such as a battery,which supplies voltage considerably in excess of the rated voltage ofthe light bulb filament.

Another object is to provide a luminous gun sight attachable to the gunat a point immedii ately beneath the barrel, thereby enabling the gunand gunsight to be inserted in a compact holster, as well as locatingthe gun sight in a position where it is not in the way of the user if hedesires to use the regular sights on the top of the gun.

Another object is to provide a luminous gun sight, all parts of whichare self-contained, in a compact casing mounted beneath the barrel ofthe gun in the vicinity of the muzzle, thereby making the gunmuzzle-heavy, a condition which pistol experts generally favor foraccurate shooting, in contrast to a muzzle-light condition.

Another object` is to provide a luminous gun sight having agravity-responsive switch, such as a mercury switch, for automaticallyenergizing the gun sight as the gun is raised into aiming and firingposition, but de-energizing the gun sight when the gun is lowered or ismaintained in a lowered position, as in a holster, or when held at theusers side.

Another object is to provide a luminous gun sight as set forth in theobject immediately preceding, wherein a safety switch is provided inseries with the gravity-responsive switch, the safety switch beingoperated by. the holster to cie-energize the electrical system, therebypreventing the gun sight from becoming illuminated when the gun is laidon a shelf or table in a horizontal position in its holster, therebysaving current.

Another object is to provide a luminous gun sight as set forth in thetwo objects immediately preceding, wherein an additional hand-operatedswitch is provided to by-pass the gravity-responsive switch so that inan emergency the user can switch on the luminous gun sight when he mustshoot downward, as in shooting down a stairway, downhill, or from a roofor window.

In the drawing:

Figure 1 is a central vertical section. through a preferred form of theluminous gun sight of this invention.

Fig. 2 is a top plan view of the luminous gun sight shown in Figure 1.

Figure 3 is a front elevation of the luminous gun sight shown in Figure1.

Figure 4 is a rear elevation, partly broken away, of the luminous gunsight shown in Figure 1.

Figure 5 is a horizontal longitudinal section taken along the line 5-5in Figure 1.

Figure 6 is a fragmentary vertical cross-section taken along the line 66 in Figure 1.

Figure 7 is a similar View of a modification of a portion of Figure 6,showing a modified reticule or sighting indicia.

Figure 8 is a diagrammatic View of the electri- Y cal circuit of theluminous gun sight of this invention.

Figure 9 is a side elevation partly in section showing the luminous gunsight attached to a pistol of the revolver type.

Figure 10 is a top plan view of the arrangement shown in Figure 9.

General arrangement In general, the luminous gun sight in the preferredform of this invention consists of a compact casing attachable to thebarrel or forward portion of a gun and containing an optical projectionsystem with batteries for supplying current to energize the electriclightbulb used as the source of light for the projecting system. Theluminous gun sight is attached to a pistol of the revolver type bysliding a tubular portion over the barrel of the pistol and rotating ituntil the front sight of the pistol locks against an abutment.

The optical projecting system consists of a condensing lens having areticule, preferably etched thereon, or optionally, upon a separateplate or using separate cross-wires. Optionally, also, a light filamentitself may be used as the reticule, or sighting index. The opticalsystem is also provided with one or more objective lenses for projectingthe image of the reticule upon the target. The axis of the opticalsystem is arranged at an angle to the axis of the gun bore so that anyerrors of parallax, drift or other deviation may be compensated for.

The optical system also contains an electric light bulb which serves toilluminate the reticule. The filament of the electric light bulb isenergized by one or more battery cells, these battery cells supplying avoltage which is considerably in excess of the rated voltage of thefilament. By this means the electric light bulb is caused to deliver amuch more brilliant illumination than is possible in using a bulb of thesame rated voltage as the voltage of the batteries. Thus the life of thelight bulb lament is necessarily shortened, but this shortening is notserious when it is remembered that the gun sight is used onlyintermittently for short periods of time. Under such circumstances, ithas been proved experimentally that the light bulb lament has a life farlonger than its life for steady burning at the excess voltage at whichit is operated.

The energization of the light bulb is controlled by a gravity-responsiveswitch, such as a mercury switch, so arranged that the circuit is brokenwhen the gun is pointed downward, but closed when the gun is raised.With this arrangement, the user, such as a policeman, watchman orsoldier, does not need to disclose his position until the instant he isready to re, and the gun sight becomes illuminated automatically when heraises the gun to fire.

In order to avoid the waste of current when the gun is placed in ahorizontal position in its holster, an additional safety switch isprovided in series with the gravity-responsive switch so that engagementwith the holster opens this switch and cle-energizes the electricalsystem. Optionally, an additional hand-operated switch is provided forby-passing the gravity-responsive switch or mercury switch so that theuser can employ the luminous gun sight in shooting downward, as downhill, down a stairway, or from a roof or upper window.

Construction Referring to the drawing in detail, Figures 1 to Il show apreferred embodiment of the luminous gun sight of this invention ashoused in a casing l, preferably of metal or molded plastic material.The casing IG is provided with an upper bore ll, a lower bore l2, andintermediate bores i3 and lil running longitudinally therethrough. Thecasing lil is provided with front and rear closure plates i5 and I6 heldtogether by a longitudinal screw il threaded into thel threaded bore I 8in the rear plate. In order to prevent short-circuiting the electricalsystem, it is preferable that the rear plate i6 shall be of insulatingmaterial, or that the screw l1 shall be insulated from one of the platesl5 or I6.

The casing lil is provided with an upper projection I9 to which issecured a tubular member 20 as by the bolts or rivets 2l (Figure l). Thetubular member 2li is provided with a longitudinal slot 22 offset fromthe vertical and communicating with a set-back portion 23 having anabutment 2li forming a part thereof. In attaching the device to a pistolof the revolver type, the tubular portion 2) is slid over the barrel ofthe revolver with the front sight of the gun passing through the slot 23and coming to rest in the offset portion 23 against the abutment 24as'the device is rotated into its working position, rlhe tubular member26 is also provided with an access hole 25 to prevent the insertion of ascrew driver for tightening or loosening the bolts 2l.

The upper bore I i serves to receive the optical projection system. Thisconsists oi a convex condensing lens Zd having a reticule 2l associatedtherewith. The reticule 2l may consist of cross lines 28 (Figure 6)either alone or associated with a circle 253 (Figure '7). Other indiciamay be employed in the reticule 2l, as desired by the user or as'adaptedto the particular conditions under which the gun sight is to be used.

The optical system also contains a convex objective lens 3l) having itsprincipal focus coinciding with the cross-lines 28 of the reticule 2l.

The cross-lines 28 may be conveniently etched upon the rear surface ofthe condensing lens 255 Ior placed upon a separate plate, as is mostconvenient. The condensing lens 25 and objective lens 3S are separatedfrom each other maintained in accurate positions relatively to eachother and to the source of illumination by spacing tubes 3|, 32 and 33,the latter being in abutting relationship with the front closure platel5.

The source of illumination consists of an electric light bulb 3d havinga filament 35 and a tubular base 5?. The latter is permanently securedwithin a holder 3l' of disk-like form by means 30 of a metallic insert33. The metallic insert 33 is preferably of low melting alloy, such asan alloy of bismuth and antimony or solder.

The purpose of the metallic insert S3 is to enable the :filament to beaccurately located ex- 35 actly in the axis of the cylindrical outersurface 3S of the holder El. Ordinarily, the filaments 35 of light bulbsare often eccentric to their bases 36 so that accurate adjustmentrelatively to the axis of an optical projecting system varies with theparticular bulb. In the present invention, the bulb 34 is seated in theholder 3'! by means of a jig in the laboratory of the manufacturer ofthe gun sight and adjusted until the filament 35 is exactly co-axialrelative to the outer surface 39 o the holder 3l, after which theuseable metal S3 ,is allowed to solidify. This arrangement increases theoptical accuracy of the projecting system,

The electrical system by which the lainent 35 is energized consists of apair of battery cells 40 inserted in the lower bore I2. The central polelil of the rearward cell il@ is in engagement with the metallic casingd2 of the forward cell, whereas the central pole lll of the forward cellis in engagement with the forward plate l5. Contact is made with thecasing i2 of the rearward cell lil by means of a spring member d3 whichis provided with an aperture M surrounding the screw il and preventingcontact therewith. rlhe upper end of the spring member 43 is secured tothe holder Sl, which is of conducting material and which is held inposition by the set screw d5 passing through a hole in the casing IG andhaving its threads engaging a threaded hole 46 in the holder 3l. Thefuseable metal 38 establishes a circuit between the holder Si and thebase 3S of the light bulb 3d.

Secured to the central pole 41 of the light bulb 34 is a conductor d8which passes downward (Figure 4) through an aperture d and through theintermediate bore lil to the rear pole 5i of a gravity-responsivemercury switch 52. The rear pole 5l is insulated as at 53 from theswitch casing 5d, which contains a quantity of mercury 55. Thev switchcasing E4 is slidably mounted in a bore enlargement 55 and is urgedtoward the forward end thereof into engagement with the front closureplate l by a coil spring 5l. The switch casing 54 is provided with aforward projection 53 which projects through an aperture 59 in the frontclosure plate l5. Consequently, the closure plate l5 completes thecircuit, as shown in Figure 8, between the battery cells t2 and thelight bulb filament 35, except when the device is in a vertical positionor when the projection 58 and the mercury switch 52 are pushed backwardas by engagement with the holster. When either of these situationsoccurs, the circuit is broken and the lament 35 remains deenergized.

Optionally, an additional switch is provided for by-passing the mercuryswitch 52 and establishing a Contact between the front closure plate l5and the conductor d8. The purpose of this manually operated switch is toenable the lament 35 to be illuminated when the police ofiicer or otheruser finds it necessary to shoot downward from an elevation. Withoutthis manual switch, the filament 35 cannot be energized when the gun ispointed downward and is only energized when the gun is raised toward ahorizontal or upward vertical position.

This manual switch 63 is pivotally mounted on the rear end of the screwi7, and is engageable with a spring contact Sli, the inner end of whichengages the central pole lil of the light bulb 34. This enables the bulb34 to be energized, regardless of the position of the mercury switch 52.

Operation In the operation of the luminous gun sight of this invention,it is assumed that the batteries i2 have been loaded into the lower borel2 and the end closure plates i5 and i5 secured in the positions shownin Figure l. The circuit is now complete except for its possibleinterruption by the mercury switch 52.

The device is attached to the gun by sliding it over the barrel with thefront sight passing through the slot 22 into the cutaway position 23 asdescribed above. Obviously, suitable means of attaching the device to anautomatic pistol or to a rie, shotgun or sub-machine gun will be evidentby slight modifications of this arrangement.

The holster for the gun is preferably made in substantially rectangularshape so that it will accommodate the device in its position upon thegun. When the gun and luminous gun sight are thus assembled, as inFigure 9, and secured in the holster, the contact with. the bottom wallof the holster pushes the projection 53 and switch 52 inward out ofcontact with the end closure plate iii. This breaks the electricalcircuit and prevents the lighting of the lament 35 of the bulb Se eventhough the gun and its holster are laid in a horizontal position. Assoon as the operator removes the gun from the holster, however, the coilspring 51 pushes the mercury switch 52 to the left, bringing its frontedge into engagement with the end closure plate l5 and conf ditioningthe circuit for closure as soon as the gun is raised.

As long as the user keeps the gun lowered, the mercury in the mercuryswitch 52 is out of contact with the switch pole 5i and no current caniiow to the light bulb lament 35. Thus, a police ofcer, watchman,detective or soldier does not need to disclose his position to apossible criminal or enemy while he is waiting for a favorableopportunity to act. If, however, he finds it necessary to use the gun,he merely raises it to a horizontal position in the natural act ofsighting the gun. As he does this, the mercury 55 ows into contact withthe switch pole 5i and closes the circuit shown in Figure 8, causing thelight bulb lament to become illuminated. This causes an image of thereticule 2l with its cross lines 23 to be projected upon the distanttarget, with the cross lines intersecting at the point where the bulletwill strike. The user may thus raise his gun and fire, lowering itquickly before his opponent has an opportunity to sight accurately andfire. Moreover, the user can hold the pistol around one side of anobstacle such as a barrel or tree while he peers around the oppositeside, thereby deceiving the opponent into thinking that he is behind thegun instead of to one side of it.

Moreover, the use of batteries d2 which supply voltage considerably inexcess of the voltage rating of the light bulb filament 35 causes abrilliant illumination to occur and the cross lines 23 to be sharplyseen on the target against a bril liant circular patch of light. Thisfeature gives the device great superiority over previously used deviceswhere the dimness of image and the lack of contrast greatly interferedwith the accuracy of shooting.

Figure 9 shows the relationship of the axis 6i! 'of the gun bore ascompared with the axis Si of the optical system of the gun sight. Theaxis Si is seen to be angled upward slightly so as to compensate forparallax, drift and other errors of trajectory. The angle of inclinationbetween the axes and 5I in Figure 9 is somewhat exaggerated to indicatethe principle more clearly. Obviously, the trajectory of the bullet willalso have much influence upon the adjustment of the luminous gun sight,especially if it is adjusted for shooting at distances greater than theordi nary distances, or is used with cartridges having low ballisticcharacteristics.

While I have shown and described my invention in detail, it is to beunderstood that the same is to be limited only by the appended claimsfor many changes may be made without departing from the spirit and scopeof my invention.

What I claim is:

1. In a luminous gun sight, an electric light source, a sighting elementassociated therewith, an optical system arranged to project an image ofsaid sighting element to a distant location, means for supplyingelectricity to said light source, gravity-responsive means forinterrupting the circuit between said light source and saidelectricity-supplying means in response to the lowering of the gun sightfrom a raised position, and means for selectively closing said circuitindependently of said gravity-responsive means in the lowered positionof the gun.

-2. In a luminous gun sight, an electric light source, a sightingelement associated therewith, an optical system arranged to project animage of said sighting element to a distant location, means forsupplying electricity to said light source at a voltage materially inexcess of the rated voltage of said light source whereby to increasebrilliance of said distant image, a gun holster, and switch meansoperatively engageable with said holster for opening the circuit betweensaid light source and said electricity-supplying means.

3. In a luminous gun sight, an electric light source, a sighting elementassociated therewith, an optical system arranged to project an image ofsaid sighting element to a distant location, a gun holster and meansautomatically responsive to engagement with the gun holster object forcle-energizing said light source.

4.. In a luminous gun sight an electric light source, a sighting elementassociated therewith, an optical system arranged to project an image ofsaid sighting element to a distant location, a gun holster, and switchmeans operatively engageable with said holster for opening the circuitbetween said light source and said electricitypplying means.

5. a luminous gun sight, an electric light source, a sighting elementassociated therewith, an optical system arranged to project an imagesaid sighting element to a distant location, a gun holster, switch meansoperatively engageable with said holster for opening the circuit betweensaid light source and said electricity-supplying means, andgravity-responsive switch means in series with said holster switch meansfor respectively clcsing and opening the circuit between said lightsource and said electricity-supplying means in response to the raisingand lowering of the gun sight.

6. En a luminous gun sight, a casing having a hansb-er, an electriclight source in said chamer, a sighting element and an opticalprojecting ystem arranged in said chamber for forming a distant image ofsaid sighting element, an electric battery. a circuit interconnectingsaid battery d light source, switch means for selectiven ng and closingsaid circuit, and a tubular t therein longitudinally slidable over thebarrel of a gun and having a slot therein for the passage ci" the frontsight of the gun whereby to quickly attach and detach the gun sight fromthe gun barrel while maintaining accurate alignment therebetween.

7. ln a luminous gun sight, a casing having a plurality of adjacentelongated chambers, an electric light source in a rst chamber, asighting element and an optical projecting system arranged in said firstchamber for forming a distant image of said sighting element, anelectric battery in a second chamber, a circuit interconnecting saidbattery with said light source, switch means for selectively opening andclosing said circuit, and a tubular attachment member having a boretherein longitudinally slidable over the barrel of a gun and havingmeans therein for the passage of the front sight o the gun, whereby toquickly attach and detach the gun sight from the gun bar rel whilemaintaining accurate alignment therebetween.

8. In a luminous gun sight, a casing having a plurality of adjacentelongated chambers, an electric light source in a first chamber, asighting element and an optical projecting system arranged in said firstchamber for forming a distant image of said sighting element, anelectric battery in a second chamber, a circuit interconnecting saidbattery with said light source, switch means for selectively opening andclosing said circuit, and an attachment member on said casing above saidchambers having a bere for receiving a gun barrel and a slot for thepassage of the iront sight of the gun, whereby t0 quickly attach anddetach the gun sight from the gun barrel while maintaining accuratealignment therebetween.

9. In a luminous gun sight, a casing having a plurality of adjacentelongated chambers, an electric light source in a rst chamber, asighting element and an optical projecting system arranged in said iirstchamber for forming a distant image ci said sighting element, anelectric battery in a second chamber, a circuit interconnecting saidbattery with said light source, switch means for selectively opening andclosing said circuit, and an attachment member on said casing above saidchambers having a bore for receiving a gun barrel and a slot for thepassage of the front sight `0f the gun, said slot having an offsetportion for receiving said front sight in a locking position, whereby toquickly attach and detach the gun sight from the gun barrel whilemaintaining accurate alignment therebetween.

GEORGE HOWLETT DAVS.

